循环荷载作用下泥炭质土动力累积特性试验研究

发布时间：2018-03-31 13:20

本文选题：土力学　切入点：泥炭质土　出处：《岩石力学与工程学报》2017年05期

【摘要】：工程实践中,泥炭质土由于富含有机质,具有高含水量、低密度、超高压缩性以及低强度的异常力学特性,往往被视为问题土。针对昆明地区交通荷载作用下泥炭质土的动力响应特征,选取滇池草海附近典型泥炭质土,开展考虑围压水平、动应力幅值以及静偏应力影响的不排水循环三轴试验,研究该土的长期累积变形特性。研究表明:研究土样具有典型泥炭质土特征,表现为含水量181.5%~259.3%,密度1.10~1.22 g/cm~3、有机质含量29.9%~53.0%,有机物质分解度较高;动应力幅值和静偏应力对昆明泥炭质土的长期动力特性影响显著,大动应力幅值和静偏应力加剧累积变形和孔压的发展,同时,当动应力水平小而静偏应力大时,累积塑性变形的发展速度反而大;虽然初始围压对累积变形影响较小,但对残余孔压的影响显著。此外,基于双对数坐标下累积应变速率与循环周次关系以及前人研究方法,建立了泥炭质土累积塑性应变与动荷载循环周次间的经验关系。
[Abstract]:In engineering practice, peat soil is often regarded as a problem soil because of its rich organic matter, high moisture content, low density, ultra-high compressibility and low strength.According to the dynamic response characteristics of peat soil under traffic load in Kunming area, the undrained cyclic triaxial test was carried out considering the influence of confining pressure, dynamic stress amplitude and static deflection stress on typical peat soil near Caohai, Dianchi Lake.The long-term cumulative deformation of the soil is studied.The amplitude of large dynamic stress and static deflection stress aggravate the development of cumulative deformation and pore pressure. At the same time, when the dynamic stress level is small and the static deflection stress is large, the development speed of cumulative plastic deformation is larger, although the initial confining pressure has little effect on cumulative deformation.However, the residual pore pressure is significantly affected.In addition, based on the relationship between cumulative strain rate and cyclic cycles in double logarithmic coordinates and previous research methods, the empirical relationship between cumulative plastic strain and cyclic cycles of peat soil is established.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;中原工学院建筑工程学院;天津城建大学土木工程学院;
【基金】：国家自然科学基金资助项目(41402277,41672293) 国家重点基础研究发展计划(973)项目(2010CB732101)~~
【分类号】：TU41

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